Hi Jerome, I haven't tried GLSL on older hardware so I can't provide an directly wisdom. Does your driver support OpenGL 2.0? If so then fragment shaders should be supported, even if only in software.
As for osg::Program, like OpenGL it supports having just a vertex shaders or just a fragment shaders as well as both, so if you don't attach any fragment shaders then the normal fixed function pipeline should be used. Since I haven't tested against older hardware/drivers I can't say whether the code will require all extension to be present even if it doesn't need it. If this is the case then osg::Program could probably be refactored to allow this, or simply just subclass from osg::Program. The other alternative is simply to buy a new card for your machine, you'll be able to pick up a GLSL supporting card pretty cheaply, even the low end ones will kick the 4200's butt in performance as well as features. Robert. On 11/29/06, Jerome Jeannin <[EMAIL PROTECTED]> wrote:
Hi everyone, I have some question about the way to use GLSL vertex shader in OSG. As far as I know, osg::Program can be used only if those OpenGL extension are supported : GL_ARB_shader_objects, GL_ARB_vertex_shader, GL_ARB_fragment_shader and GL_ARB_shading_language_100 (regarding to GL2Extensions::isGlslSupported) On some hardware (like my TI4200), GL_ARB_fragment_shader is not available, so I can't use osg::Program. I agree that Glsl is not fully supported, but it would support Glsl vertex shader. So, what is the good way for me to use vertex shader ? - using osg::VertexProgram rather than osg::Program ? (but ARPvp is not so fun to my eyes) - extend osg::Program to a less restrictive one ? - extend osg::Geometry/Drawable and write my own drawImplementation to support my vertex shader ? Thanks, Jérôme _______________________________________________ osg-users mailing list [email protected] http://openscenegraph.net/mailman/listinfo/osg-users http://www.openscenegraph.org/
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